Far from being an aging energy source from the XIXth century or a mere symbol of the industrial revolution, coal is still massively used worldwide today, which raises many issues. It accounts for 25% of the global energy mix and consumption is still on the rise (+37% between 2000 and 2008), driven by the energy needs of emerging countries, especially for electricity generation purposes.

Old fuel, new ways

There are two ways to generate electricity from coal. The older method consists in crushing and pulverizing it in order to burn it. Coal combustion boils water to produce steam and drive turbines. This method is rather inefficient, as it does not optimally tap the potential energy deriving from fuel combustion. Nevertheless, this kind of power plant is still widespread because it is responsive to shifts in electricity consumption and can cover occasional peaks.

The more efficient fluidized bed method consists in giving coal the shape of a bed suspended in pressurized air before burning it. This technique is more efficient, for coal is burnt at lower temperature (900°C, compared with 1400°C for the oldest power stations). Besides, coal of poorer quality can be used, which makes this method even more profitable.

Like any fossil fuel, coal is the result of a nearly 300 million-year-old vegetal decomposition process; it is made up of over 90% carbon. There are two kinds of coal: surface coal and steam coal (also known as coke). Surface coal is to be found in shallow underground locations and is suited for open-pit mining. Surface coal became the object of heavily industrialized, mechanized and efficient exploitation. Steam coal, however, can only be found deep underground, which makes its exploitation more complicated and less profitable. This resource is still tapped in some developing countries, but the little productivity of its extraction as well as the low quality of the fuel make it of limited interest.

A rather abundant and cheap but extremely polluting resource

Available on all continents, easy to harness and thus a cheap resource, (surface) coal is massively used by states endowed with large reserves (China, Australia or Poland, 88% of whose electricity comes from coal). However, its high carbon concentration makes burning coal much more polluting than other carbon-based fuels, such as petrol or natural gas. Coal combustion releases large amounts of CO2 but also methane and a number of other pollutants. In a 2007 report, the French Senate pushed for research on “clean coal” to be further conducted, especially on CO2-capturing technologies.

Europe is endowed with rather little coal reserves; nonetheless, it can still count on 6% of worldwide resources. Although the Old Continent historically based the development of its industry on this energy source, today it is no longer the subject of consensus. Disagreement was amplified by Germany’s and then Italy’s decision to phase out nuclear energy, which led contradictors to fear that Germany might massively resort to coal, although it denies it. The fourth larger coal consumer in the world after China, the United States and India, the European Union so far does not seem capable of reconciling the diverging energy interests of its member states.